Try:
app.comoponent.ts
export class AppComponent {
Angular: Observable<any[]>;
constructor(db: AngularFireDatabase){
this.Angular = db.list('/Angular').valueChanges();
}
app.component.html
<ul *ngIf="Angular">
<li *ngFor= "let course of Angular | async">
{{course}}
</li>
</ul>
If you use async pipe then change detection will allways kick in when observable emits a value, in your case Angular
.
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